A review on friction stir welding (FSW) process for dissimilar aluminium to steel metal systems

Friction stir welding is a promising method for joining dissimilar metals. The transportation industries are increasingly focussing on enhancing the fuel efficiency of vehicles because of environmental regulations and costs. A solution to this problem can be manufacturing structures having the combination of both high-strength steel alloy as well as lightweight aluminium alloy. Researchers have been drawn towards solid-state joining techniques like friction stir welding (FSW) because of the challenges encountered in fusing steel and aluminium through traditional fusion welding methods. Unlike fusion welding, FSW does not involve the melting of parent materials. This review paper has made an effort to provide a comprehensive overview of the current research and development in the field of dissimilar FSW steel-Aluminium systems. The paper highlights the influence of Tool material and designs and also the influence of process parameters on weld quality. Moreover, the paper investigates the microstructural characteristics, Intermetallic compounds, mechanical properties, and common defects of dissimilar FSW joints, focusing on factors influencing joint strength and hardness. Furthermore, the environmental sustainability aspects of dissimilar have been discussed. Finally, existing variants and potential research areas are identified to enhance improved mechanical properties and process efficiency.